Multi-spectral analysis of fine scale aurora
The Aurora Borealis is the visible manifestation of the complex plasma interaction between the solar wind and the Earth's magnetosphere and ionosphere. Ground based and in situ measurements demonstrate a prevalence of dynamic fine structure within auroral displays, with spatial scales down to t...
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KTH, Rymd- och plasmafysik
2010
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ftkthstockholm:oai:DiVA.org:kth-24907 2023-05-15T16:04:50+02:00 Multi-spectral analysis of fine scale aurora Dahlgren, Hanna 2010 application/pdf http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-24907 eng eng KTH, Rymd- och plasmafysik Stockholm : KTH Trita-EE, 1653-5146 2010:040 orcid:0000-0001-5596-346X http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-24907 urn:isbn:978-91-7415-749-9 info:eu-repo/semantics/openAccess Fusion Plasma and Space Physics plasma och rymdfysik Atom and Molecular Physics and Optics Atom- och molekylfysik och optik Doctoral thesis, comprehensive summary info:eu-repo/semantics/doctoralThesis text 2010 ftkthstockholm 2022-08-11T12:33:09Z The Aurora Borealis is the visible manifestation of the complex plasma interaction between the solar wind and the Earth's magnetosphere and ionosphere. Ground based and in situ measurements demonstrate a prevalence of dynamic fine structure within auroral displays, with spatial scales down to tens of metres and time variations occurring on a fraction of a second.The fine-scale morphology is related to structuring of auroral currents and electric fields and detailed spatial, spectral and temporal observations of the aurora are crucial in understanding the electrodynamic processes taking place in the ionosphere and in its coupling to the magnetosphere. In this thesis, the low-light optical instrument ASK (Auroral Structure and Kinetics) is used to image small-scale structures in the aurora at very high spatial and temporal resolution. ASK is a multi-spectral instrument, imaging the aurora in three selected emissions simultaneously. This provides information on the energy of the precipitating electrons. The SIF (Spectrographic Imaging Facility) instrument has been used in conjunction with ASK, to give a more complete picture of the spectral characteristics of the aurora, and to determine the degree of contaminating emissions present in the same spectral interval as the emission lines observed by ASK. Data from ASK and SIF are used to study the relation between the morphology and dynamics of small-scale structures in the aurora and the energy of the precipitating electrons. By comparing electron density profiles provided by EISCAT (European Incoherent SCATter) radar measurements with modeling results, information on the characteristic energy and the energy flux of the precipitating electrons can be obtained. One of the ASK channels is imaging a metastable O+ emission, which has a lifetime of about 5 s. By tracing the afterglow in this channel optically a direct measure of the E x B drift is obtained from which the local ionospheric electric field can be calculated. ASK data has also been used to analyse the ... Doctoral or Postdoctoral Thesis EISCAT Royal Institute of Technology, Stockholm: KTHs Publication Database DiVA |
institution |
Open Polar |
collection |
Royal Institute of Technology, Stockholm: KTHs Publication Database DiVA |
op_collection_id |
ftkthstockholm |
language |
English |
topic |
Fusion Plasma and Space Physics plasma och rymdfysik Atom and Molecular Physics and Optics Atom- och molekylfysik och optik |
spellingShingle |
Fusion Plasma and Space Physics plasma och rymdfysik Atom and Molecular Physics and Optics Atom- och molekylfysik och optik Dahlgren, Hanna Multi-spectral analysis of fine scale aurora |
topic_facet |
Fusion Plasma and Space Physics plasma och rymdfysik Atom and Molecular Physics and Optics Atom- och molekylfysik och optik |
description |
The Aurora Borealis is the visible manifestation of the complex plasma interaction between the solar wind and the Earth's magnetosphere and ionosphere. Ground based and in situ measurements demonstrate a prevalence of dynamic fine structure within auroral displays, with spatial scales down to tens of metres and time variations occurring on a fraction of a second.The fine-scale morphology is related to structuring of auroral currents and electric fields and detailed spatial, spectral and temporal observations of the aurora are crucial in understanding the electrodynamic processes taking place in the ionosphere and in its coupling to the magnetosphere. In this thesis, the low-light optical instrument ASK (Auroral Structure and Kinetics) is used to image small-scale structures in the aurora at very high spatial and temporal resolution. ASK is a multi-spectral instrument, imaging the aurora in three selected emissions simultaneously. This provides information on the energy of the precipitating electrons. The SIF (Spectrographic Imaging Facility) instrument has been used in conjunction with ASK, to give a more complete picture of the spectral characteristics of the aurora, and to determine the degree of contaminating emissions present in the same spectral interval as the emission lines observed by ASK. Data from ASK and SIF are used to study the relation between the morphology and dynamics of small-scale structures in the aurora and the energy of the precipitating electrons. By comparing electron density profiles provided by EISCAT (European Incoherent SCATter) radar measurements with modeling results, information on the characteristic energy and the energy flux of the precipitating electrons can be obtained. One of the ASK channels is imaging a metastable O+ emission, which has a lifetime of about 5 s. By tracing the afterglow in this channel optically a direct measure of the E x B drift is obtained from which the local ionospheric electric field can be calculated. ASK data has also been used to analyse the ... |
format |
Doctoral or Postdoctoral Thesis |
author |
Dahlgren, Hanna |
author_facet |
Dahlgren, Hanna |
author_sort |
Dahlgren, Hanna |
title |
Multi-spectral analysis of fine scale aurora |
title_short |
Multi-spectral analysis of fine scale aurora |
title_full |
Multi-spectral analysis of fine scale aurora |
title_fullStr |
Multi-spectral analysis of fine scale aurora |
title_full_unstemmed |
Multi-spectral analysis of fine scale aurora |
title_sort |
multi-spectral analysis of fine scale aurora |
publisher |
KTH, Rymd- och plasmafysik |
publishDate |
2010 |
url |
http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-24907 |
genre |
EISCAT |
genre_facet |
EISCAT |
op_relation |
Trita-EE, 1653-5146 2010:040 orcid:0000-0001-5596-346X http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-24907 urn:isbn:978-91-7415-749-9 |
op_rights |
info:eu-repo/semantics/openAccess |
_version_ |
1766400480101007360 |